The invention relates to a lock assembly for a door. More particularly, the invention relates to a lock assembly that includes a housing and a plug.
Generally, some lock assemblies include a housing and a plug that define respective pin chambers to receive pin pairs. The pin pairs include outer pins substantially disposed within the housing, and inner pins disposed within the plug. Springs are often used to bias the pin pairs toward a key slot defined in the plug. More specifically, the springs are engaged with the outer pins, which in turn engage the inner pins and force the inner pins into the key slot. In the absence of a correct or proper key, the outer pins are partially disposed in the plug and block rotation of the plug within the housing.
The plug is rotatable relative to the housing in most conventional lock cylinders. A shear line is defined where the plug and the housing meet. When a proper key is inserted into the key slot, the inner pins are moved. Movement of the inner pins moves the respective outer pins so that the junctions of the inner pins and the outer pins are aligned with the shear line. This allows the plug to be turned to an unlocked position such that the outer pins are disposed completely in the housing, and the inner pins are disposed completely in the plug.
Some existing lock assemblies include an interchangeable core that has a housing and a plug that allow re-keying or replacement of the lock assembly. Interchangeable core lock assemblies permit re-keying of locks without opening the door or removing the lock from the door. Typically, existing housings and plugs are designed specifically for a particular lock type, and these interchangeable cores have mounting structure that is also designed specifically for the lock type in which the interchangeable core is used. Existing interchangeable cores are relatively complicated and are often manufactured using complex machining and manufacturing processes. For example, a knob lock assembly, a lever lock assembly, and deadbolt lock assembly each utilize a particular interchangeable core. These arrangements often complicate re-keying and/or replacement of the lock assembly.
Existing mortise lock assemblies include a one-piece housing that is inserted into an opening in a door or other structure, and that is engaged with a mortise chassis in the door to lock and unlock the door. These lock assemblies also include multiple anti-drill pins to limit tampering with the lock assembly, and a plug that is specifically sized for the mortise housing. To accommodate doors that have different thicknesses, existing mortise lock assemblies require multiple housings and plugs that are sized to conform to different door thicknesses. In particular, each housing and plug in existing mortise lock assemblies are designed to fit one door thickness, and cannot be used in lock assemblies that are applied to a door of a different thickness.
Some existing lock assemblies include a cam attached to the housing assembly and to a separate driver that is disposed in the housing assembly to move a latch between a locked position and an unlocked position. Often, a washer spaces the driver from the cam, and the cam is attached to the driver by a separate screw. Typically, the driver and the screw are inserted into the housing assembly through an opening in the front of the housing assembly. The cam is engaged with a rear of the housing assembly, and is attached to the driver using the screw.
During operation of the lock assemblies that include the cam, the driver is rotated by the plug, which in turn causes rotation of the cam to move the latch between the locked and unlocked positions. Often, the screw is loosened by operation of the lock assembly, which can disengage the cam from the driver. Disengagement of the cam from the driver can prevent the cam from moving the driver between the locked and unlocked positions. In some lock assemblies, a friction washer and/or a thread adhesive applied to the screw can be used to temporarily delay loosening of the cam from the housing assembly.